1. Field of the Invention
The present invention relates to a method for fabricating a semiconductor substrate.
2. Background of the Related Art
As semiconductor devices are becoming more highly integrated and their design rules are changed, the aspect ratio of a contact hole or a via hole has become larger, thus decreasing the reliability of an interlayer contact. Accordingly, in order to improve the reliability in an interlayer contact, a plug is generally formed in a contact hole or in a via hole. The plug is generally formed in the contact hole or in the via hole by etching an insulation layer to form a contact hole or a via hole, forming a conductive material layer on the upper surface of the insulation layer and in the contact hole or in the via hole, performing a Chemical Mechanical Polishing (CMP) process on the conductive material layer until the upper surface of the insulation layer is exposed and finally performing post-washing to remove residual particles produced during the Chemical Mechanical Polishing process.
However, the method for forming a plug of a semiconductor device has various problems. For example, after the Chemical Mechanical Polishing process is finished and before the post-washing begins, the semiconductor wafer is exposed to ambient air for a considerable time period. During this time, particles in the ambient air are adsorbed onto the upper surface of the semiconductor wafer, which degrades the efficiency of the post-washing process, as well as, increases the surface defects in the semiconductor substrate.
The particles of the ambient air are adsorbed onto the surface of the semiconductor substrate because after the Chemical Mechanical Polishing process is finished, the surfaces of the insulation layer and of the conductive layer are exposed to the ambient air, the surface of the insulation layer and the conductive layer is a polysilicon layer which is in a hydrophobic state. Accordingly, a rapid dry phenomenon occurs because of its hydrophobic state on the surface of the polysilicon layer, which causes the particle residue produced during the Chemical Mechanical Polishing process and the particles in the ambient air to be adsorbed onto the surface of the semiconductor substrate.
Thus, since the particles are adsorbed onto the surface of the semiconductor substrate, the post-washing process hardly removes the particles, thus degrading the efficiency of the post-washing process and increasing the surface defect of the semiconductor substrate.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.
An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.
Another object of the present invention is to provide a method for reducing surface defects of a semiconductor substrate.
Another object of the present invention is to change the surface of a semiconductor substrate from a hydrophobic to a hydrophilic state.
A further object of the present invention is to heighten the efficiency of the post-washing process.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a method for reducing surface defects of a semiconductor substrate including processing the surface of a semiconductor substrate by using a chemical solution between a Chemical Mechanical Polishing process and a post-washing process.
To achieve the above object, there is also provided a method for reducing surface defects of a semiconductor substrate including a step of oxidizing the surface of a semiconductor substrate between the Chemical Mechanical Polishing process and the post-washing process.
To achieve the above object, there is also provided a method for reducing surface defects of a semiconductor substrate including a step of performing the Chemical Mechanical Polishing process by adding a chemical solution as an additive to a slurry for the Chemical Mechanical Polishing process.
To further achieve the above object, there is also provided a method for reducing surface defects of a semiconductor substrate by selectively etching an insulation film formed on a semiconductor substrate and forming a contact hole, forming a conductive layer in a contact hole and on the upper surface of the insulation film, performing a Chemical Mechanical Polishing process on the conductive layer to expose the upper surface of the insulation film and forming a conductive layer plug in the contact hole, processing the upper surface of the conductive layer plug with a chemical solution and washing the conductive layer plug and the surface of the insulation film.
In the above method, in the step of processing the surface of the conductive layer plug with a chemical solution, the surface of the plug is changed from a hydrophobic state to a hydrophilic state.
In the above method, the step of forming the plug and the step of forming the oxide layer on the upper surface of the plug are simultaneously performed.
To achieve the above objects of the present invention in whole or in parts there is provided a method for reducing surface defects of a semiconductor substrate that includes selectively patterning an insulation film formed on a semiconductor substrate to form at least one contact hole, forming a conductive layer in the contact hole and on the insulation film, polishing the conductive layer to remove a portion of the conductive layer and expose a surface of the insulation film thus forming a conductive layer plug which remains in the contact hole, forming an oxide film on a surface of the conductive plug, and washing the oxide film and the insulation film.
To further achieve the above objects of the present invention in whole or in parts there is provided a method for reducing surface defects of a semiconductor substrate that includes selectively patterning an insulation film formed on an upper surface of a semiconductor substrate and forming a hole, forming a conductive layer in the hole and on an upper surface of the insulation film, performing a polishing process with slurry on the conductive layer to remove portions of the conductive layer to expose the upper surface of the insulating film and form a conductive layer plug which remains in the contact hole and also to simultaneously form an oxide film on the upper surface of the plug, and washing the upper surface of the conductive layer plug and of the insulation film.
To further achieve the above objects of the present invention in whole or in parts there is provided a semiconductor wafer with reduced surface defects that includes a semiconductor substrate, a selectively formed insulating layer with a hole, a first conductive layer formed in the hole, and an oxide film with a bottom surface adjacent to the upper surface of the first conductive layer.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.